Mercedes Details Its New V-6 and V-8 Engines

When it comes to gas-fueled engines, Mercedes-Benz has some catching up to do. While Audi’s FSI motors impress with their supreme efficiency and BMW’s smooth and powerful inline-sixes indeed fill us with “joy,” Germany’s most traditional premium brand offers an engine portfolio that is not clearly superior in any particular field. Now Daimler is launching […]

Jens Meiners

May 7, 2010

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When it comes to gas-fueled engines, Mercedes-Benz has some catching up to do. While Audi’s FSI motors impress with their supreme efficiency and BMW’s smooth and powerful inline-sixes indeed fill us with “joy,” Germany’s most traditional premium brand offers an engine portfolio that is not clearly superior in any particular field.

Now Daimler is launching its next generation of V-6 and V-8 engines, which are both more powerful and more efficient than the engines they replace. A new, twin-turbocharged and direct-injected 4.6-liter (4663-cc) V-8 replaces the current, naturally aspirated 5.5-liter V-8. At 429 hp, power rises by 12 percent. Torque grows to 516 lb-ft, up from 391 lb-ft. Mercedes says the turbocharged 4.6-liter engine delivers the power of a 7.0-liter V-8. The engine is force-fed by one turbocharger per cylinder bank; the intercooler is placed in the engine’s valley. An engine stop-start system is included, and in the CL-class coupe, fuel economy is rated at 25 mpg in the European cycle. The new V-8 will be launched in the CL first and then in the S-class.

The new 3.5-liter V-6 will be launched first in a naturally aspirated variation, making 302 hp and 273 lb-ft of torque, increases of 34 hp and 15 lb-ft over the current 3.5-liter. Thus equipped, an S350 is claimed to return a surprising 31 mpg. The new engine will be rolled out over the entire Mercedes-Benz portfolio, starting with the CL, the S-class, and the next-generation CLS. Historically, we haven’t been offered sixes in the larger Benzes, but fuel-economy concerns—and the return of BMW’s inline-six 7-series to our shores—could change that.

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These are just two manifestations of M-B’s next engine generation, which is not a from-scratch effort, but rather an extension of the current V-6 and V-8 engine family. Future variations will include turbocharged V-6 engines and variants with different power levels. On that note, AMG’s 536-hp, turbocharged 5.5-liter V-8, which makes its debut in the 2011 S63 AMG, is related to the new engine generation. The high-performance arm also will get a high-revving, naturally aspirated version of the eight.

On the more responsible side of the spectrum, Mercedes is planning to use both the V-6 and the V-8 in hybrid models. It says that the extraordinary fuel economy shows the potential of large-displacement petrol engines, and the potential of internal-combustion engines altogether.

The turbocharged versions, in particular, will give the competition something to chew on. Audi is still largely betting on naturally aspirated big-power engines, which are at this point lacking in torque. BMW, on the other hand, has the power and torque but needs its turbo engines to deliver their promised fuel economy not just on paper, but also in the real world. We’ll soon see whether the new Mercedes engines can live up to their lofty fuel-economy claims while making that all-important power.